Micron, the US's biggest maker of memory chips, has said it is being investigated for anti-competitive practices by the US Justice Department.

Last month, Micron ditched plans to buy into Korean chip giant Hynix after months of talks failed to produce a deal.

Micron was also proposing to spend $3bn to take a 15% stake in the rump of the Korean firm.

"After careful evaluation, we are unable to discern a process that would allow the numerous parties involved to reach agreement in a timely manner," Micron chairman Steve Appleton said.

Thursday's announcement leaves Hynix's fate in the hands of creditors owed more than $5bn.